Rubio came out swinging, saying: “Here's a guy who inherited $200 million, if he hadn’t inherited $200 million, you know where he'd be right now? Selling watches in Manhattan.”

Referring to Trump's proposal to build a wall along the Mexican border, Rubio added: "If he builds the wall the way he built Trump Towers, he'll be using illegal immigrant labor to do it."

The jab referred to a 1983 lawsuit that claimed undocumented workers from Poland built the Trump Towers in New York City. Trump claimed he didn't know they were unauthorized to work, which lawyers from the other side disputed.

Trump denied the charges, claiming he didn’t know they were unauthorized. The lawsuit was eventually settled.

Cruz then jumped in, saying: “Marco is exactly right that a federal court found Donald guilty of being part of a conspiracy to hire people illegally and entered a $1 million judgment against him.”

Rubio would not let up, saying: “Even today, we saw a report in one of the newspapers that Donald, you've hired a significant number of people from other countries to take jobs that Americans could have filled.

“My mom was a maid at a hotel, and instead of hiring an American like her, you have brought in over 1,000 people from all over the world to fill those jobs instead."

Trump defended his hiring of foreign workers, saying: “People didn’t want to have part-time jobs” and that “you can’t get help in those hot, hot sections of Florida.”

Nearly every time the Republican frontrunner tried to speak and defend himself, he was met with either Cruz or Rubio.

Rubio said: “He says five things: everyone’s dumb, he’s going to make America great again. Win, win, win, he’s winning in the polls. And the lines around the states. Every night. Same thing.”

Eventually Trump had enough and called Rubio “a choke artist” and Cruz “a liar.”

On CBS This Morningon Friday, Rubio continued the attacks on the real estate mogul, calling him a “con artist.”

"A con artist is about to take over the Republican party and the conservative movement and we have to put a stop to it," Rubio said on Friday.

He added: “He refuses to answer questions in any specific public policy. He has no plans for health care, for example. They asked him about the debt, he claimed that he's gonna cut the debt by cutting fraud and abuse. He didn't get any follow-up or any press on that... We're about to turn over the conservative movement to a person that has no ideas of any substance on the important issues."